Blasting agent primer and tubular explosion train



Dec. 12, 1967 a s. ROUSH 3,357,355

BLASTING AGENT PRIMER AND TUBULAR EXPLOSION TRAIN Filed June 13, 1966 INVEN TOR (5.5. ROUSH v A 7' TORNE V6 United States Patent Ofiice 3,357,355 Patented Dec. 12, 1967 3,357,355 BLASTING AGENT PRIMER AND TUBULAR EXPLOSION TRAIN Gale S. Roush, Bartle'sville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed June 13, 1966, Ser. No. 556,964

Claims. (Cl. 102- 24) ABSTRACT OF THE DISCLOSURE An explosion train primer is provided which is threadable at both ends into explosion cartridges and which contains a thirnble for a detonating cap in a recess therein sealed therewith extending upwardly and obliquely inwardly, there being holes for lead wires in opposite walls of said primer, one of said holes being below said thimble to avoid disconnecting the lead wires from said cap when positioning said train in a borehole.

This invention relates to a primer for use in a tubular explosion train and to such a train including said primer.

In order to initiate an explosion in the nitro-carbonitrate family of blasting agents, a high velocity primer is required. Dynamite or similar explosive materials are utilized in a primer associated with the blasting agent for initiating the explosion, utilizing an ordinary dynamite cap to set off the primer. Water-tight tubular packages of blasting agents have been developed because of the frequency of the occurrence of water in the hole drilled for the blasting or seismic explosion.

One of the problems encountered is that of incorporating the primer in the train of explosive packages intermediate the ends thereof which is frequently desirable. Available primers to be utilized in a train of explosion packages have their ignition caps on the end so that the primer must be placed on the end of the train where the ignition cap is available or exposed for ignition. Another problem is that of holding the explosion train at the bottom of the hole when water invades the hole and would normally cause the explosion train to float and rise in the shot hole. A further problem occurs when sand invades the shot hole and requires some technique for forcing the explosion train thru the invading sand to the bottom of the hole.

A system of tubular water-proof sealed rigid thermoplastic containers for explosives has been developed with provision in each end of the packages for threading together end-to-end. Such a system is disclosed and claimed in U.S. application S.N. 412,811 of Tony E. Branscum and Estil N. Barnes, filed Nov. 20, 1964, now Patent No. 3,306,200.

This invention is concerned with a high velocity primer which may be attached at either end to a cartridge in a train of explosive cartridges so that the primer may be positioned at either end of the train or at an intermediate position therein.

Accordingly, it is an object of the invention to provide an improved high velocity primer or primer case for a high velocity explosive which may be water-tight and adaptedfor insertion in an explosion train of cartridges at any selected point or location. Another object is to provide a primer or primer case which is attachable to the lower end of an explosion train and is provided with a simple and effective anchoring means. Another object is to provide a combination of a high velocity primer or primer case, an easily attachable anchor, and pointed nose section therefor. A further object is to provide an improved explosion train containing a high velocity primer which is positioned intermediate the ends of the train and readily ignitable therein. Other objects of the invention will become apparent to one skilled in the art upon consideration of the accompanying disclosure.

A broad aspect of the invention comprises a tubular primer case having a male threaded section on one end and a female threaded section on the other end, the female threaded section forming a male threaded section on the outer circumference thereof which is threaded or screwed into a surrounding female threaded section on the inner wall of said other end. The threaded male section is closed on the outer end and forms a continuation of the main body section of the tubular primer case. The other end of the primer case is closed by a closure member comprising a section of tube containing male threads on the outer circumference and female threads on the inner circumference, male threads of this closure being threadable into female threads in said other end of the case. The female threaded section on this closure member is made to receive the male threaded end section of another case so that other tubes or cases of similar structure may be connected thereto by screwing them together.

An anchoring device is also provided which has a threaded collar adapted to be threaded over the male threaded end of the tube and leaving a space on this threaded end for threading on a pointed nose when the primer is to be utilized on the lower end of the explosion train. The anchor includes a plurality of rearwardly and outwardly biased anchoring arms which are deflected rearwardly when lowering the train into the shot hole and penetrate the wall of the shot hole when the train tends to rise in the hole.

A more complete understanding of the invention may be had by reference to the accompanying schematic drawing of which FIGURE 1 is an elevation of an explosive cartridge form for converting into an explosive cartridge; FIGURE 2 is a similar view in exploded form of a primer case in partial section, an anchor, and a pointed nose section for the primer case; FIGURE 3 is an elevational view of an explosion train with the primer inserted therein and attached thereto; FIGURE 4 is a pictorial view of the anchor for the explosion train; and FIGURE 5 is an elevational view of a combination pointed nose section and anchoring device for attaching to the lower end of an explosion train.

The cartridge form shown in FIGURE 1 is substantially identical to that disclosed as FIGURE 1 in the aforesaid copending application of Branscum and Barnes. The cartridge form 10 includes a cartridge case 11 and a closure member 12 therefor. The case comprises an elongated tubular body section 13 which preferably is formed with ridges 14 therein to provide reinforcing and better grip when handling and a forward male closure section 16 joined to body section 13 by truncated conical section 18. The rearward end of the form is also closed in a similar manner by closure 12 comprising male threaded section 20 and a rearward section 22 containing a seal ring groove 24 attached to section 20 by another truncated conical section numbered 26. Section 22 is tapered or flared slightly so that the maximum diameter of same is the section at dotted line 28. Just forward of rearward section 22 is a threaded section 30 of reduced diameter providing female threads internally into which the male section 20 of closure 12 threads to close the rearward end of the tube. In order to insert the closure, rearward section 22 is cut along dotted line 28 and the severed member is reversed and threaded into section 30, as clearly illustrated in FIGURE 2 which is discussed herein below. Male threads 20 not only mesh with female section 28, but also provide a set of female threads on the internal circumference thereof which provides for threading thereinto another male section having a configuration of section 16 so that other cartridges of similar configuration may be connected to provide a train of any desired length.

The cartridge form illustrated in FIGURE 1 is formed of thermoplastic material by blow molding or similar process as fully disclosed in said copending application. The form may be made from any of the rigid polymers suitable for molding, such as polyethylene, polypropylene, or olefins of this character copolymerized with minor amounts of other olefins such as butenes and polyvinyl chloride.

The primer case of FIGURE 2 is blow molded of similar material and by a similar method to that utilized in forming the cartridge form of FIGURE 1. The primer case is provided with a male threaded nose section 32 joined to the main body section 34 by a truncated conical section 36. Nose section 32 is substantially identical to nose section 16 of the cartridge form of FIGURE 1. Rearward section 38 is joined to main body section 34 by a threaded section 40 of reduced diameter containing internal female threads which mesh with the male threads on closure section 42. This closure section 42 is preferably made integral with the case by blow molding in the same manner as closure 12 in FIGURE 1. While a seal ring 44 is shown forming a seal between cylindrical section 46 and the inner wall of section 38, this seal ring may be omitted as well as the groove therefor when the primer case is to be loaded with a primer explosive inert to water (dynamite). Cut-away section 48 in the main body section 34 exposes a dynamite composition or other high-velocity primer compound 50. This explosive material is usually introduced to the case in semi-solid form thru the rearward end of the case. This is'followed by screwing the rearward end closure member into section 40. The semi-solid composition generally utilized sets up to a solid material after a short period of standing.

An opening or recess 52 in the circumferential wall of section 34 is made in any desired manner to provide for a dynamite cap 54 for detonating the explosive which then activates the explosion of the nitrate type explosive in the explosion cartridge or train. Electrical lead wires 56 extend from contact with the end of cap 54 along the case and then thru openings 58 and 60 and to ground level for detonating the cap. Ordinarily, when utilizing a primer composition unaffected by water, cap 54 may be inserted thru the wall of the tube by merely punching a hole of suitable size therein and extending the cap thru the hole. This technique may also be utilized in threading leads 56 thru the primer case. When it is desirable to make the primer case water-tight, a plastic thimble 52 may be inserted thru an opening in the case wall and seal therewith; cap 54 then is inserted into the thimble. Likewise, a seal may be formed around openings 58 and 60 for lead wires 56.

The positioning of lead wires 56 as shown is effective in preventing the loosening of same from the cap during low ering of the explosion train downhole.

Anchor 62 comprises a collar 64 provided with female threads which screw onto male threaded end 32 of the primer case or section 16 of the explosion cartridge of FIGURE 1. A pair of rearwardly and outwardly fixed and biased anchor arms 66 are integral with collar 64. This :anchor device is preferably formed of rigid thermoplastic or other readily moldable material. However, it may be formed of metal or other rigid material which is sufiiciently flexible to allow arms 66 to be distorted inwardly during lowering of the explosive train into the hole and which grip and penetrate the walls of the shot hole when the train is moved upwardly. Collar 64 is sufiiciently narrow to leave a substantial uncovered section on elements 16 and 32 for threading on noseelement 70.

Nose element 70 is pointed forwardly so as to be bulletshaped and is provided with a hollow rearward female .threaded section 72 for threading onto the forward end .of a primer case or explosion cartridge. A hole '74 in the of nose section permits running a line therethru and fastening same for lowering the train into the shot hole.

FIGURE 3 shows a series of explosion cartridges 11 made in accordance with the method and structure defined in connection with FIGURE 1 connected in a train with a primer case 33. Primer case 33 is inserted intermediate the ends of the train but it may also be attached at either end of the train.

FIGURE 4 is a pictorial view of the anchor 62 of FIG- URE .2 and needs no further explanation.

Combination nose and anchor member 76 of FIGURE 5 is similar to nose 70 of FIGURE 2, having female threaded internal section 78, but it is provided with anchoring steel bars 80 which are biased outwardly and rearwardly by springs, one end 82 of which is embedded in the plastic material forming the nose section, the other end 83 locking over arms 80. Pins 84 provide for rotation of the arms 80 into the position shown by dotted lines 86 during the lowering of the train in the hole and, upon attempting upward movement of the train, arms 80 engage the wall of the hole and tend to penetrate the surrounding formation and anchor the train downhole. Nose sections 70 and 76 may be fabricated of metal or other suitable moldable material. It is preferred to fabricate these nose sections of thermoplastic material similar to that utilized in the primer and explosion cartridge cases.

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

I claim:

1. A primer cartridge comprising in combination:

(a) an elongated tubular body closed at one end by a male threaded section of reduced diameter;

(b) a male threaded tubular closure similar to that of (a) threaded axially and inwardly into a female threaded section in the other end of said body, the external threads of said tubular closure forming internal female threads adapted to receive a threaded male section conforming to that of (a);

(c) a recess in the midsection of the side of said body of (a) for a detonating cap, said recess extending obliquely toward the female threaded end of said tubular body and including a thimble therein sealed to said body, and

(d) a pair of holes in opposite walls of said body of (a) for passing lead wires thru said body and connecting same with a cap in said recess of (c), one of said holes being on the same side of said body as said recess'and intermediate said recess and the threaded section of (a).

2. The cartridge of claim 1 made of thin-walled thermoplastic material.

3. The cartridge of claim 1 including a solid explosive composition substantially filling the body of (a), a cap in the recess of (c) capable of detonating said explosive, and lead wires passing from said cap thru the holes of (d) in sealed relation with said body.

4. An explosion train comprising in combination: (a) a series of explosion cartridges, each containing a difficultly explodable solid composition sealed therein, each said cartridge having opposite male and female threaded ends corresponding to the male and female threaded ends of the primer cartridge of claim 1; and (b) a primer cartridge constructed as in claim 1, said explosion cartridges and said primer cartridge being threaded together into an elongated train and said primer cartridge being loaded with a detonating explosive for the composition of (a). V 5. The train of claim 4 including a cap in the recess, of said primer cartridge and lead wires extending from said cap thru said holes. 7

6. The train of claim 4 wherein said primer cartridge is attached to an explosion cartridge at each end.

7. The train of claim 4 wherein said is on the end of said train.

8. The train of claim 7 including an anchor on the outer end of said primer cartridge comprising radially oblique arms foldable along the wall of said primer cartridge during lowering of said train in a shot hole and biased outwardly away from said cartridge.

9. The train of claim 7 including a generally pointed nose threaded onto the free outer end of said primer cartridge.

10. The primer cartridge of claim 1 including an anchor having outwardly and rearwardly biased arms attached to a collar threaded onto the male section of said body and a pointed nose section threaded onto said male section adjacent and forwardly of said anchor.

primer cartridge References Cited UNITED STATES PATENTS Duesing 10224 Silverman 10221.6 Meredith et a1. 10224 Robinson, et al. 10221.6 Branscum et a1. 102-24 SAMUEL W. ENGLE, Primary Examiner.

BENJAMIN A. BORCHELT, Examiner. V. R. PENDEGRASS, Assistant Examiner. 

1. A PRIMER CARTRIDGE COMPRISING IN COMBINATION: (A) AN ELONGATED TUBULAR BODY CLOSED AT ONE END BY A MALE THREADED SECTION OF REDUCED DIAMETER; (B) A MALE THREADED TUBULAR CLOSURE SIMILAR TO THAT OF (A) THREADED AXIALLY AND INWARDLY INTO A FEMALE THREADED SECTION IN THE OTHER END OF SAID BODY, THE EXTERNAL THREADS OF SUCH TUBULAR CLOSURE FORMING INTERNAL FEMALE THREADS ADAPTED TO RECEIVE A THREADED MALE SECTION CONFORMING TO THAT OF (A) (C) A RECESS IN THE MIDSECTION OF THE SIDE OF SAID BODY OF (A) FOR DETONATING CAP, SAID RECESS EXTENDING OBLIQUELY TOWARD THE FEMALE THREADED END OF SAID TUBULAR BODY AND INCLUDING A THIMBLE THEREIN SEALED TO SAID BODY, AND 